“He doesn’t need my counsel because he knows what it is: Run!,” the former president told ABC’s Diane Sawyer in an interview broadcast on Wednesday when asked about the possibility of former Florida Gov. Jeb Bush running for the nation’s highest office. “Whether he does or not is an incredibly personal decision.”

While Bush certainly has an enthusiasm for his little brother, his own legacy and a sense of “Bush fatigue” could drag down any Jeb candidacy.

“He would be great,” George W. Bush said. “He’d be a marvelous candidate if he chooses to do so.”

Bush went on a media blitz Wednesday and Thursday, doing interviews with all three major television networks before his presidential library opens later Thursday. President Barack Obama, along with former President Bill Clinton and Bush’s father, former President George H.W. Bush, is expected to attend the opening.

In an interview with CBS’s Charlie Rose that aired Thursday, Bush said he was “impressed” by the progress made on comprehensive immigration reform this spring, something he admitted he was “not very successful” at.

“The problem with an issue like immigration is that there are a lot of moving parts,” he said. “And a single moving part can end up disturbing a lot of people. And sometimes people focus on the moving parts as opposed to the whole. But I hope they get something done. And I’m impressed by the efforts thus far to get something done.”

The former president also praised the government’s response to the bombing of the Boston Marathon’s finish line, which killed three and wounded more than 250.

“I’ve been very impressed by the response at all levels of government,” he said.

Rose asked Bush if he still would’ve invaded Iraq if he had known intelligence indicating Saddam Hussein had weapons of mass destruction was incorrect.

“That’s an impossible question to answer,” Bush said. “Because as far as we were concerned, in my administration, as well as every other intelligence agency, we all thought he had weapons of mass destruction. … Which was confirmed in a way by the fact that he would not allow weapons inspectors into his country. And so the question we all were saying was, “What is he hiding?’ Perhaps my biggest surprise is he didn’t take me seriously.”

In an interview with NBC’s Matt Lauer in the library’s replica of Oval Office, Bush said he is happy to have left the presidency.

“No,” Bush said when asked if the fake Oval made him miss the real one. “I had all the fame and power I needed for eight years. Laura and I knew when our time was up, it was time to come home.”

Bush also told Sawyer painting had been a life-changing experience for him.

“I love to paint,” the former president told Sawyer in an interview that aired the night before his presidential library and museum are set to open in Dallas. “Painting has changed my life in an unbelievably positive way.”

Bush’s artistic handiwork drew national attention earlier this year when several images of his paintings — including ones featuring bath tubs and showers — popped up online.

“It may reflect my precocious nature, me painting myself in a bath tub or in a shower,” he said with a laugh.

Striking a more serious note, he said the paintings were a good way to stay engaged, something his father — former President George H.W. Bush — continues to do.

“The actual lesson is, you can keep learning in life,” Bush said. “Someone said to me, ‘man, you deserve to rest.’ And I don’t want to rest. I want to live life, I want to follow the example of President 41 and, you know, sprint into the grave.”

His painting teacher has told news outlets that “He’s going to go down in the history books as a great artist.”